The invention relates to an apparatus for utilizing the energy present in flowing water, comprising a shaft on which a blade wheel is mounted.
Such apparatus is known in the embodiment of water-mills having an undershotwheel or overshotwheel respectively. With such devices a gradient in the waterflow at the position of the blade wheel is always used, so that the blades at the downstream side of the bladewheel are not loaded by the resistance of the water present at that side.
Such a gradient does not prevail in a river or other flowing water. In order to permit the utilization of the energy present therein the apparatus according to the invention is characterised by a support in which a shaft is rotatably journalled. The support is adapted to be floatingly moored in the flowing water, and a blade wheel is mounted on the shaft. The blade wheel has radial blades, each provided with gate openings and with a slide or damper movable relative to the blade in the radial direction of the wheel. The slide is likewise gated and is biased, as with one or more springs towards a closed position. The gates are opened due to the rotation of the wheel through a cam profile which is secured to the support and cooperates with the outer end of the slide in the radial direction.
The cam profile causes the gates to be closed only in that portion of the path traversed by the blades in which the flowing water imparts a positive force to the blades, which causes a driving moment around the wheel shaft.
The blade wheel shaft may be positioned substantially horizontally as well as substantially vertically in the water. In the vertical position the blade wheel may be connected to the support such that the complete width of the blades, as measured in the direction of the shaft, is found below the water level. The cam profile then sees to it that the blades are opened when they move against the water flow direction. A vertical positioning is advantageous, if the water flow velocity is extremely high since the backwardly moving blades then impart a larger braking action than with horizontal positioning and prevents the rotary velocity of the shaft becoming too high.
With horizontal positioning of the shaft it is preferable that the shaft be mounted to the support such that it is situated some distance above the water level. The blades then experience a resistance because of the water mass if the force component of the water flow acting thereon is small, i.e. the angle of the blade with the flow direction is still small (when initially immersing the blade into the water) or is small again respectively (when the blade leaves the water). The air resistance experienced during the backward movement of the blades through the air is smaller due to the open position of the gates.
Of course the apparatus may be multiplied by providing a plurality of blade wheels on the shaft or on different shafts. The shaft or shafts are adapted to be coupled to the input shaft of an electric generator or other machine to be driven. If therewith a second blade wheel is mounted to the same shaft such that the blades thereof show a phase-shift relative to the blades of the first blade wheel, which phase-shift is equal to half the mutual angular spacing of the blades, a more constant driving moment around the shaft is obtained.
The invention will hereunder be illustrated with reference to the drawing, showing an embodiment as an example of the apparatus according to the invention.